US7518281B2 - Electric motor with a housing for at least two carbon brushes - Google Patents

Electric motor with a housing for at least two carbon brushes Download PDF

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Publication number
US7518281B2
US7518281B2 US10/511,286 US51128605A US7518281B2 US 7518281 B2 US7518281 B2 US 7518281B2 US 51128605 A US51128605 A US 51128605A US 7518281 B2 US7518281 B2 US 7518281B2
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US
United States
Prior art keywords
carbon brushes
holder
collector
pivot bearing
electric motor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related, expires
Application number
US10/511,286
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English (en)
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US20060087196A1 (en
Inventor
Winfried Habel
Otto Baumann
Siegfried Fehrle
Andre Ullrich
Michael Weiss
Hardy Schmid
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
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Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Assigned to ROBERT BOSCH GMBH reassignment ROBERT BOSCH GMBH ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: BAUMANN, OTTO, FEHRLE, SIEGFRIED, HABEL, WINFRIED
Publication of US20060087196A1 publication Critical patent/US20060087196A1/en
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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K5/00—Casings; Enclosures; Supports
    • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/14—Means for supporting or protecting brushes or brush holders
    • H02K5/143—Means for supporting or protecting brushes or brush holders for cooperation with commutators
    • H02K5/148—Slidably supported brushes
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K2205/00—Specific aspects not provided for in the other groups of this subclass relating to casings, enclosures, supports
    • H02K2205/06—Machines characterised by means for keeping the brushes in a retracted position during assembly
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49009—Dynamoelectric machine
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/53—Means to assemble or disassemble
    • Y10T29/5313—Means to assemble electrical device
    • Y10T29/53143—Motor or generator

Definitions

  • the present invention relates to an electric motor with a holder for at least two carbon brushes, which are pressed by spring force in the radial direction against the jacket face of a cylindrical collector fixed to the armature shaft of the motor.
  • the holder with the carbon brushes can be pulled off the collector in the axial direction of the armature shaft by way of a pivot bearing that holds the armature shaft, and that means which cover the pivot bearing against the entry of dirt are provided, on their side toward the holder with the carbon brushes, with one or more chamfers that extend in such a way that the carbon brushes slide over it as the holder is being pulled off and in the process are thrust radially outward counter to the spring force.
  • the invention makes simple removal of the holder with the carbon brushes possible.
  • an armature disk may be disposed between the pivot bearing and the collector, and/or a bearing dome may be placed on the pivot bearing. Unhindered pulling off of the holder with the carbon brushes over the pivot bearing is made possible by providing that the side of the armature disk and/or of the bearing dome oriented toward the collector is provided with a chamfer extending rectilinearly or in curved form.
  • FIG. 1 a is a fragmentary longitudinal section through an electric motor, with a carbon brush holder disposed on its collector and with means of a first embodiment for protecting the armature shaft pivot bearing from soiling;
  • FIG. 1 b is a magnified portion of the fragmentary longitudinal section depicted in FIG. 1 a ;
  • FIGS. 2 a - 1 through 2 e - 1 depict various positions of a carbon brush as the holder for the carbon brushes is being pulled off from the armature shaft of the motor;
  • FIGS. 2 a - 2 through 2 e - 2 depict magnified portions of the various positions depicted in FIGS. 2 a - 1 through 2 e - 1 , respectively;
  • FIG. 3 a depicts a fragmentary longitudinal section through an electric motor, with a carbon brush holder disposed on its collector and with means of a second embodiment for protecting the armature shaft pivot bearing from soiling;
  • FIG. 3 b is a magnified portion of the FIG. 3 a fragmentary longitudinal section.
  • FIG. 1 a a portion of an electric motor of the kind used preferably in hand-operated electrical tools, is shown. Since the motor is constructed rotationally symmetrically with respect to its longitudinal axis, only half of the electric motor is shown in FIG. 1 a .
  • the motor has a rotatable armature 1 , whose armature shaft, on its end remote from the armature 1 , is supported in a pivot bearing 3 .
  • a cylindrical collector 4 which rotates with the armature shaft 2 is disposed on the armature shaft 2 , between the armature 1 and the pivot bearing 3 for the armature shaft 2 .
  • the collector 4 is provided with electrical contact by at least two carbon brushes, of which only one carbon brush 5 is shown in the sectional view in FIG. 1 a .
  • the carbon brushes have the function of establishing an electrical connection from an external power connection to the collector of the motor.
  • the carbon brushes 5 are disposed in a holder 6 and are pressed by a spring force in the radial direction against the jacket face of the cylindrical collector 4 .
  • the spring force is exerted by a spring 7 , which rests on the face end, remote from the collector 4 , of the carbon brushes 5 and exerts a contact pressure in the direction of the jacket face of the collector 4 .
  • the holder 6 for the carbon brushes 5 is releasably fixed to the housing 8 of the motor.
  • the releasable fixation is preferably effected by means of a detent element 9 , which is present in the holder 6 and can be snapped into the housing 8 .
  • a special receptacle chamber 10 into which the holder 6 for the carbon brushes 5 is insertable, may be integrally formed onto the housing 8 .
  • An armature disk 11 is disposed on the armature shaft 2 , between the collector 4 and the pivot bearing 3 .
  • This armature disk 11 serves to protect the pivot bearing 3 for the armature shaft 2 against the entry of material abraded from the carbon brushes 5 as well as from particles (such as drilling dust and drillings), which are aspirated in the process of operating an electrical power tool.
  • This armature disk 11 has a larger diameter than the collector 4 and therefore protrudes radially past the collector 4 , as is readily apparent from the magnified portion of the FIG. 1 a fragmentary longitudinal section that is depicted in FIG. 1 b.
  • the pivot bearing 3 of a motor is covered by a bearing dome 12 .
  • the bearing dome 12 is a caplike structure, communicating with the housing 8 , which covers the pivot bearing 3 and the armature shaft, placed in the pivot bearing, on the face end remote from the collector and which, with a preferably flattened, cylindrical wall 13 , coaxially surrounds the pivot bearing 3 .
  • FIGS. 2 a - 1 through 2 e - 1 five different positions of the carbon brush 5 are shown during the process of pulling off the holder 6 for the carbon brushes 5 .
  • FIGS. 2 a - 1 through 2 e - 1 shows only one carbon brush 5 with the spring 7 holding it down, without the holder 6 .
  • FIGS. 2 a - 2 through 2 e - 2 depict magnified portions of the various positions depicted in FIGS. 2 a - 1 through 2 e - 1 , respectively.
  • FIGS. 2 a - 1 and 2 a - 2 the holder is moved in the axial direction, so that the brushes 5 slide over the collector 4 in the direction of the armature disk 11 . Finally, the carbon brushes 5 meet the armature disk 11 , which protrudes radially past the collector 4 . This situation is shown in FIGS. 2 b - 1 and 2 b - 2 . Because of the larger diameter of the armature disk 11 in comparison with the collector 4 , this would prevent the holder 6 with the carbon brushes 5 from being pulled farther in the X direction and thus from being removed entirely from the motor.
  • the armature disk 11 on its side toward the carbon brushes 5 , is provided with a chamfer 14 , which decreases from the outer diameter of the armature disk 11 to the carbon brushes 5 , the carbon brushes slide along this chamfer 14 over the armature disk 11 , and in the process the carbon brushes 5 are thrust radially outward counter to the force of the spring 7 .
  • FIGS. 2 a - 2 through 2 e - 2 depict the position of the carbon brushes 5 relative to the armature disk 11 and to the bearing dome 12 .
  • FIGS. 2 c - 1 and 2 c - 2 show the position of the carbon brushes 5 once they have been slipped over the chamfer 14 of the armature disk 11 as far as the outermost point of the armature disk 11 .
  • the carbon brushes slide over the topmost point of the armature disk 11 , until they meet the bearing dome 12 . This situation is shown in FIGS. 2 d - 1 and 2 d - 2 .
  • the bearing dome 12 is likewise provided with a chamfer 15 .
  • This chamfer of the bearing dome 12 decreases in diameter from the outermost diameter of the cylindrical wall 13 in the direction of the carbon brushes 5 .
  • a bearing dome 12 that has a somewhat larger diameter than the armature disk 11 is no hindrance to the continued motion of the holder 6 with the carbon brushes 5 . That is, the carbon brushes 5 slide over the chamfer 15 of the bearing dome and are thrust outward, counter to the force of the spring 7 , until the carbon brushes 5 finally rest on the surface of the cylindrical wall 13 of the bearing dome 12 .
  • the holder 6 with the carbon brushes 5 disposed in it can be pulled all the way off, over the surface of the cylindrical wall 13 of the bearing dome 12 .
  • the chamfers 14 and 15 on the armature disk 11 and bearing dome 12 can extend rectilinearly, as shown in the drawings, or can have a curved course.
  • the armature disk 11 is provided, on its side toward the bearing dome 12 , with a chamfer 16 , which enables the carbon brushes 5 to be thrust without hindrance from the bearing dome 12 over the armature disk 11 onto the collector 4 .
  • This chamfer 16 on the armature disk 11 is actually required only whenever the outer diameter of the bearing dome 12 is less than the outer diameter of the armature disk 11 . This is because only for that case would the armature disk 11 be a hindrance as the holder 6 , with the carbon brushes 5 , is being slipped on in the direction of the collector 4 .
  • FIG. 3 a differs from the exemplary embodiments shown in FIGS. 1 a , 1 b , and 2 a - 1 , 2 a - 2 through 2 e - 1 . 2 e - 2 only in the design of the means that protect the pivot bearing 3 against dirt.
  • All the other details of the exemplary embodiment in FIGS. 3 a , 3 b correspond to those of the exemplary embodiment of FIGS. 1 a , 1 b , and 2 a - 1 , 2 a - 2 through 2 e - 1 . 2 e - 2 and are identified by the same reference numerals.
  • FIGS. 1 a , 1 b correspond to those of the exemplary embodiment of FIGS. 1 a , 1 b , and 2 a - 1 , 2 a - 2 through 2 e - 1 . 2 e - 2 and are identified by the same reference numerals.
  • FIGS. 1 a , 1 b correspond to those of the
  • the bearing dome 12 protrudes, with its cylindrical wall 131 , axially in the direction of the collector 4 , past the armature disk 11 .
  • a chamfer 15 over which the holder 6 can slide is therefore required only on the face end of the cylindrical wall 131 of the bearing dome 12 oriented toward the holder 6 having the carbon brushes 5 .
  • the wall 131 of the bearing dome 12 which wall extends in the axial direction and protrudes past the armature disk 11 , moreover has the advantage that the gap between it and the armature disk 11 can be kept quite small, which leads to increased leakproofness of the pivot bearing 3 .
  • the elongation of the cylindrical wall 131 in the direction of the collector 4 has the effect of carrying cooling air directly to the collector 4 and to the carbon brushes 5 .

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Motor Or Generator Current Collectors (AREA)
  • Motor Or Generator Frames (AREA)
US10/511,286 2002-06-26 2003-05-30 Electric motor with a housing for at least two carbon brushes Expired - Fee Related US7518281B2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10228493.8 2002-06-26
DE10228493A DE10228493A1 (de) 2002-06-26 2002-06-26 Elektromotor mit einer Halterung für mindestens zwei Kohlebürsten
PCT/DE2003/001761 WO2004004094A1 (de) 2002-06-26 2003-05-30 Elektromotor mit einer halterung für mindestens zwei kohlebürsten

Publications (2)

Publication Number Publication Date
US20060087196A1 US20060087196A1 (en) 2006-04-27
US7518281B2 true US7518281B2 (en) 2009-04-14

Family

ID=29723463

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/511,286 Expired - Fee Related US7518281B2 (en) 2002-06-26 2003-05-30 Electric motor with a housing for at least two carbon brushes

Country Status (5)

Country Link
US (1) US7518281B2 (de)
EP (1) EP1520334B1 (de)
CN (1) CN100367632C (de)
DE (1) DE10228493A1 (de)
WO (1) WO2004004094A1 (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102008041717A1 (de) * 2008-08-29 2010-03-04 Robert Bosch Gmbh Handwerkzeugmaschine mit Bürstenmotor
DE102010021506B4 (de) * 2010-05-26 2012-02-23 Atlanta-Elektrosysteme Gmbh Bürstenbrücke

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4293789A (en) 1979-09-10 1981-10-06 General Motors Corporation Dynamoelectric machine brush rigging
US4311936A (en) * 1978-11-16 1982-01-19 Hitachi, Ltd. Brush holding device for electric motor
US5019741A (en) 1989-05-15 1991-05-28 Mitsuba Electric Manufacturing Co., Ltd. Brush holder device for electric motor
EP0706255A1 (de) 1994-10-04 1996-04-10 Valeo Systemes D'essuyage Kommutatorelektrische Maschine, insbesondere Gleichstromelektromotor
GB2384918A (en) 2001-10-30 2003-08-06 Bosch Gmbh Robert Rotatable brush plate for reversible electric drill

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4311936A (en) * 1978-11-16 1982-01-19 Hitachi, Ltd. Brush holding device for electric motor
US4293789A (en) 1979-09-10 1981-10-06 General Motors Corporation Dynamoelectric machine brush rigging
US5019741A (en) 1989-05-15 1991-05-28 Mitsuba Electric Manufacturing Co., Ltd. Brush holder device for electric motor
EP0706255A1 (de) 1994-10-04 1996-04-10 Valeo Systemes D'essuyage Kommutatorelektrische Maschine, insbesondere Gleichstromelektromotor
GB2384918A (en) 2001-10-30 2003-08-06 Bosch Gmbh Robert Rotatable brush plate for reversible electric drill
DE10153574A1 (de) 2001-10-30 2003-08-14 Bosch Gmbh Robert Elektromaschine

Also Published As

Publication number Publication date
EP1520334A1 (de) 2005-04-06
WO2004004094A1 (de) 2004-01-08
US20060087196A1 (en) 2006-04-27
DE10228493A1 (de) 2004-01-15
CN1666402A (zh) 2005-09-07
EP1520334B1 (de) 2020-02-19
CN100367632C (zh) 2008-02-06

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Effective date: 20210414